996 resultados para Richard I, King of England, 1157-1199


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The study undertakes a review of the Poverty Reduction Strategy Papers (PRSPs), and Interim Poverty Reduction Strategy Papers (I-PRSPs) of four selected Caribbean SIDS from the Eastern Caribbean. The countries had participated in the Poverty Reduction Strategy initiative formulated by the World Bank. The country papers reviewed were the Commonwealth of Dominica, Grenada, Saint Lucia and St. Vincent and the Grenadines. The review assesses and provides a comparative analysis of the general awareness of the notions of vulnerability and the inclusion and use of strategies that address the reduction of vulnerability and the strengthening of resilience by the countries reviewed. It also explores how vulnerability reduction strategies were applied to differing groups, as elaborated through the PRSPs.

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Objective In studies on Candida albicans adhesion to surfaces, diverse protocols have been used for collection and preparation of saliva samples. Thus, this study investigated whether variations in the centrifugation parameters and number of donors of saliva would influence the adhesion of C. albicans to a denture base resin. Methods Resin acrylic samples (n = 72) were made and then divided into four groups: (a) control – specimens were left without preconditioning in saliva; (b) three experimental groups, in which the specimens were preconditioned with saliva collected from 15 volunteers and centrifuged at 12 000 g for 5 min (G1); from 15 volunteers and centrifuged at 18 000 g for 30 min (G2); and from one volunteer and centrifuged at 12 000 g for 5 min (G3). Candida adhesion was evaluated by both the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction method and crystal violet staining. Data were analyzed by one-way analyses of variance (P = 0.05). Results For XTT reduction assay, groups G2, G3, and control were not significantly different, whereas group G1 showed significantly higher absorbance value than control. For crystal violet staining there were no significant differences among all groups. Conclusion Variations in the centrifugation parameters and number of donors of saliva may influence C. albicans adhesion to denture base resins.

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The results of the investigation on Solution Heat Treatment of Plasma Nitrided (SHTPN) precipitation-hardened steel 15-5PH are presented. The layers have been obtained by the plasma nitriding process followed by solution heat treatment at different temperatures. The influence of the solution heat treatment after nitriding on the dissolution process of the nitrided layer has been considered. The nitrided layers were studied by scanning electron microscopy, X-ray microanalysis (EDX), and X-Ray diffraction. Micro-hardness tests of the nitrided layers and solubilized nitrided layers have been carried out and interpreted by considering the processing conditions. It was found that high nitrogen austenitic cases could be obtained after SHTPN of martensitic precipitation-hardened steel (15-5PH). When Solution Heat Treatment (SHT) was performed at 1100 °C, some precipitates were observed. The amount of precipitates significantly reduced when the temperature increased. The EDX microanalysis indicated that the precipitate may be chromium niobium nitride. When the precipitation on the austenite phase occurred in small amount, the corrosion resistance increased in SHTPN specimens and the pit nucleation potential also increased. The best corrosion result occurred for SHT at 1200 °C.

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White-tailed deer (Odocoileus virginianus) have recently emerged as a source of Mycobacterium bovis infection for cattle within North America. The objective of this study was to evaluate the antibody response of M. bovis–infected deer to crude mycobacterial antigens. Deer were experimentally inoculated with M. bovis strain 1315 either by intratonsilar instillation or by exposure to M. bovis–infected (i.e., in contact) deer. To determine the time course of the response, including the effects of antigen administration for comparative cervical skin testing, serum was collected periodically and evaluated by enzyme-linked immunosorbent assay (ELISA) for immunoglobulin (i.e., IgG heavy and light chains) reactivity to mycobacterial antigens. The reactivity to M. bovis purified protein derivative (PPDb) exceeded (P < 0.05) the reactivity to M. avium PPD (PPDa) only after in vivo administration of PPDa and PPDb for comparative cervical testing of the infected deer. The mean immunoglobulin response, as measured by ELISA, of intratonsilar-inoculated deer to a proteinase K–digested whole-cell sonicate (WCS-PK) of M. bovis strain 1315 exceeded (P < 0.05) the mean of the prechallenge responses to this antigen at approximately 1 month after inoculation and throughout the remainder of the study (i.e., ~11 months). This response also exceeded (P < 0.05) that of the uninfected deer. Although this is encouraging, further studies are necessary to validate the use of the proteinase K–digested M. bovis antigens in the antibody-based assays of tuberculosis.

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Applying ecological studies to the adaptations of prehistoric human hunter-gatherer groups has greatly increased our abilities to interpret effects of an ever-changing environment and our access to critical resources on these populations. The Pleistocene/Holocene transition, its climate and human genesis in the new world, draws intensive interest from a number of scientific communities. In Twilight of the Mammoths, Paul Martin adds his views, which are of no surprise, on the megafaunal extirpations during a cultural period referred to in North America as Clovis.

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Just as there are seashells on Mt. Everest, there is an exceptional wealth of fossil remains of marine organisms preserved in the chalk of western Kansas. This Cretaceous-aged rock, and the fossils therein, were deposited at a time when a great sea cut northward across the interior of the continent around 85 million years ago, inspiring the provocative title of Everhart's book. The title is true to its subject: documentation of the Cretaceous fossils of western Kansas, their geographic and stratigraphic occurrences, and the inferences that paleontologists can make about how the organisms represented by these fossils may have once lived and interacted with one another.

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Thundering herds of bison have become synonymous with the pre-European colonization of the Great Plains. As such, they have captured the imagination of countless people, including Wes Olson, a 20-year warden for Parks Canada. Throughout Portraits of the Bison, based on both existing literature and the author's extensive experience observing and managing these animals, Olson's bison fascination is not only obvious but infectious. A remarkably talented artist as well, Olson's line drawings appear throughout the book, accompanied by Johane Janelle's photographs.

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Though intended as a field guide to the birds of the Great Plains, this book seems to serve best as a general introduction to Great Plains birds and will mostly benefit those casually interested in birds. The definition of Great Plains the book uses is rather broad, and some species are included that, in my opinion, aren't really birds of the Great Plains. For example, several warblers are included as breeding species although they nest within the book's definition of the region only in the conifer or mixed forest of north-central to northwestern Minnesota, which isn't really a part of the Great Plains proper.

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Introduction to Biology of the Acanthocephala, edited by D.W.T. Crompton and Brent B. Nickol; Cambridge University Press, 1985.

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In practice, epizootiology deals with how parasites spread through host populations, how rapidly the spread occurs and whether or not epizootics result. Prevalence, incidence, factors that permit establishment of infection, host response to infection, parasite fecundity and methods of transfer are, therefore, aspects of epizootiology. Indeed, most aspects of a parasite could be related in sorne way to epizootiology, but many of these topics are best considered in other contexts. General patterns of transmission, adaptations that facilitate transmission, establishment of infection and occurrence of epizootics are discussed in this chapter. When life cycles are unknown, little progress can be made in understanding the epizootiological aspects of any group of parasites. At the time Meyer's monograph was completed (1933), intermediate hosts were known for only 17 species of Acanthocephala, and existing descriptions are not sufficient to permit identification of two of those. Laboratory infections of intermediate hosts had apparently been produced for only two species. Study at that time was primarily devoted to species descriptions, host and geographical distribution, structure and ontogeny. Little or nothing was known about adaptations that promote transmission and the concept of paratenic hosts was unclear. In spite of the paucity of information, Meyer (1932) summarized pathways of transmission among principal groups of hosts, visualized the relationships among life cycle patterns for the major groups of Acanthocephala, and devised models for the hypothetical origin of terrestrial life cycles from aquatic ones. Nevertheless, most of our knowledge regarding epizootiology has been recently acquired.

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Moose Alces alces gigas in Alaska, USA, exhibit extreme sexual dimorphism, with adult males possessing large, elaborate antlers. Antler size and conformation are influenced by age, nutrition and genetics, and these bony structures serve to establish social rank and affect mating success. Population density, combined with anthropogenic effects such as harvest, is thought to influence antler size. Antler size increased as densities of moose decreased, ostensibly a density-dependent response related to enhanced nutrition at low densities. The vegetation type where moose were harvested also affected antler size, with the largest-antlered males occupying more open habitats. Hunts with guides occurred in areas with low moose density, minimized hunter interference and increased rates of success. Such hunts harvested moose with larger antler spreads than did non-guided hunts. Knowledge and abilities allowed guides to satisfy demands of trophy hunters, who are an integral part of the Alaskan economy. Heavy harvest by humans was also associated with decreased antler size of moose, probably via a downward shift in the age structure of the population resulting in younger males with smaller antlers. Nevertheless, density-dependence was more influential than effects of harvest on age structure in determining antler size of male moose. Indeed, antlers are likely under strong sexual selection, but we demonstrate that resource availability influenced the distribution of these sexually selected characters across the landscape. We argue that understanding population density in relation to carrying capacity (K) and the age structure of males is necessary to interpret potential consequences of harvest on the genetics of moose and other large herbivores. Our results provide researchers and managers with a better understanding of variables that affect the physical condition, antler size, and perhaps the genetic composition of populations, which may be useful in managing and modeling moose populations.

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Ozone, first discovered in the mid 1800’s, is a triatomic allotrope of oxygen that is a powerful oxidant. For over a century, research has been conducted into the synthetic application and mechanism of reactions of ozone with organic compounds. One of the major areas of interest has been the ozonolysis of alkenes. The production of carbonyl compounds is the most common synthetic application of ozonolysis. The generally accepted mechanism developed by Rudolf Criegee for this reaction involves the 1,3-electrocyclic addition of ozone to the π bond of the alkene to form a 1,2,3-trioxolane or primary ozonide. The primary ozonide is unstable at temperatures above -100 °C and undergoes cycloreversion to produce the carbonyl oxide and carbonyl intermediates. These intermediates then recombine in another 1,3-electrocyclic addition step to form the 1,2,4-trioxolane or final ozonide. While the final ozonide is often isolable, most synthetic applications of ozonolysis require a subsequent reductive or oxidative step to form the desired carbonyl compound. During investigations into the nucleophilic trapping of the reactive carbonyl oxide, it was discovered that when amines were used as additives, an increased amount of reaction time was required in order to consume all of the starting material. Surprisingly, significant amounts of aldehydes and a suppression of ozonide formation also occurred which led to the discovery that amine N-oxides formed by the ozonation of the amine additives in the reaction were intercepting the carbonyl oxide. From the observed production of aldehydes, our proposed mechanism for the in situ reductive ozonolysis reaction with amine N-oxides involves the nucleophilic trapping of the carbonyl oxide intermediate to produce a zwitterionic adduct that fragments into 1O2, amine and the carbonyl thereby avoiding the formation of peroxidic intermediates. With the successful total syntheses of peroxyacarnoates A and D by Dr. Chunping Xu, the asymmetric total synthesis of peroxyplakorate A3 was investigated. The peroxyplakoric acids are cyclic peroxide natural products isolated from the Plakortis species of marine sponge that have been found to exhibit activity against malaria, cancer and fungi. Even though the peroxyplakorates differ from the peroxyacarnoates in the polyunsaturated tail and the head group, the lessons learned from the syntheses of the peroxyacarnoates have proven to be valuable in the asymmetric synthesis of peroxyplakorate A3. The challenges for the asymmetric synthesis of peroxyplakorate A3 include the stereospecific formation of the 3-methoxy-1,2-dioxane core with a propionate head group and the introduction of oxidation sensitive dienyl tail in the presence of a reduction sensitive 1,2-dioxane core. It was found that the stereochemistry of two of the chiral centers could be controlled by an anti-aldol reaction of a chiral propionate followed by the stereospecific intramolecular cyclization of a hydroperoxyacetal. The regioselective ozonolysis of a 1,2-disubstituted alkene in the presence of a terminal alkyne forms the required hydroperoxyacetal as a mixture of diastereomers. Finally, the dienyl tail is introduced by a hydrometallation/iodination of the alkyne to produce a vinyl iodide followed by a palladium catalyzed coupling reaction. While the coupling reaction was unsuccessful in these attempts, it is still believed that the intramolecular cyclization to introduce the 1,2-dioxane core could prove to be a general solution to many other cyclic peroxides natural products.

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This book represents a collection of papers presented at a symposium in May, 1991 on the formation and paleolimnology of European maar lakes. Paleolimnological discussions embrace maar lake deposits of late Quaternary to early Tertiary age in Germany, France and Italy. The goal of the symposium and its outgrowth, this book, is to develop a funding initiative to study, core and analyze the deposits of these remarkable depositional systems.

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An experimental study on Vortex-Induced Motion (VIM) of the semi-submersible platform concept with four square columns is presented. Model tests were carried out to check the influence of different headings and hull appendages (riser supports located at the pontoons; fairleads and the mooring stretches located vertically at the external column faces; and hard pipes located vertically at the internal column faces). The results comprise in-line, transverse and yaw motions, as well as combined motions in the XY plane, drag and lift forces and spectral analysis. The main results showed that VIM in the transverse direction occurred in a range of reduced velocity 4.0 up to 14.0 with amplitude peaks around reduced velocities around 7.0 and 8.0. The largest transverse amplitudes obtained were around 40% of the column width for 30 degrees and 45 degrees incidences. Another important result observed was a considerable yaw motion oscillation, in which a synchronization region could be identified as a resonance phenomenon. The largest yaw motions were verified for the 0 degrees incidence and the maxima amplitudes around 4.5 degrees. The hull appendages located at columns had the greatest influence on the VIM response of the semi-submersible. (C) 2012 Elsevier Ltd. All rights reserved.

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A very fast, easy and efficient synthesis is described for a novel and biologically important class of 1,4-disubstituted-4-(5-pyrrolidin-2-one)-1,2,3-triazoles by an ultrasound-assisted one-pot, three-step click reaction sequence of 5-[(trimethylsilyl)ethynyl]pyrrolidin-2-one with organic azides mediated by catalytic Cu-I salts.